Plus: Watch Arcade Fire's Will Butler and Marika Shaw sing "Take Me Out to the Ballgame" during the seventh inning stretch at a Cubs game on Saturday

Last night, the National and Arcade Fire played the third of a three-show stand at Chicago's UIC Pavilion. As @ArcadeFireTube points out, Arcade Fire frontman Win Butler joined the National onstage to provide backing vocals for the Boxer standout "Start a War". Watch the clip below. The audio quality leaves something to be desired, but it's cool to see Win on stage with his fellow indie big dogs, wearing a Texas t-shirt.

While in Chicago on Saturday, Arcade Fire's Will Butler (Win's brother) and Marika Shaw also took the time to sing "Take Me Out to the Ballgame" during the Seventh Inning Stretch at the Chicago Cubs game. Watch that below as well, via We All Want Someone to Shout For.

The National: "Start a War" [ft. Win Butler] (Live in Chicago):

Arcade Fire's Will Butler and Marika Shaw sing "Take Me Out to the Ballgame" at the Cubs game: